118 THE UNIVERSITY SCIENCE BULLETIN. 



Gerris conformis Uhl. 



Habitat. Bueno said he had only found it on flowing waters, but 

 Drake says it is a lacustrine as well as a fluviatile species. To the latter 

 we owe the following notes: 



Hibernation. As an adult. 



Mating. In early spring. 



Oviposition. Eggs are deposited on material just beneath surface of 

 the water, fastened there with viscous substance which is waterproof. 



Incubation. Eleven days. 



Maturity. One adult came from the egg in 34 days. (See Ohio Nat. 

 Vol. XV, No. 7, p. 501, May, 1915.) 



Gerris marginatus Say. 



The writer reared this in the summer of 1916. The following summer 

 Mr. Bueno presented in Ent. News, 1917, a study on this insect. This is 

 our common small Gerris, and is usually winged. 



Habitat. On quiet pools and ponds as well as brooks and streams. 



Hibernation. As an adult. 



Mating. As figured on Plate XV. May last from a few minutes to 

 many hours, during which time the female rows over the surface and 

 darts here and there in pursuit of prey as though unincumbered. 



Oviposition. The eggs are laid as in G. 7-emigis. 



Number of Instars. Five instars, each requiring from 3 days to a 

 week. 



Food Habits. Similar to G. remigis. 



DESCRIPTION OF STAGES. 

 The Egg. 



Size. Length, 3 mm.; diameter, 1 mm. 



Shape. Elongate cylindrical. 



Color. White when first laid, changing to dark color before hatching. 



The Instars. 



Described in July number of Ent. News, 1917. 



Gerris canaliculatus Say. 



Habitat. Bueno tells us this species likes secluded little coves and bays 

 in ponds. 



Number of Instars. Bueno says there are five; that he reared thirty 

 individuals from one apterous female, and every one was macropterous. 



Genus TENOGOGONUS Stal. 

 Tenogogonus hesione Kirk. 

 Drake has given us what we know about this species. 

 Habitat. A lacustrine species, mostly apterous, active and congre- 

 gating in immense numbers near the shore in sheltered places. 



